Guard intervals for multi-user high efficiency (HE) wireless local area network (WLAN) communication

Abstract

An access point (AP) in a high efficiency (HE) wireless local area network (WLAN) may transmit a message specifying to a group of stations a guard interval from one of two different guard intervals. The AP may receive responses from the group of stations with the specified one of the two different guard intervals for multi-user uplink HE WLAN communication.

What is claimed is: 
     
       1. An access point (AP) comprising:
 a transceiver configured to communicate in a wireless local area network (WLAN); and 
 a processor configured to: 
 send, via by the transceiver, a first message to a first group of stations of a plurality of stations, wherein the first message is configured to enable the first group of stations to identify a first guard interval of a plurality of different guard intervals; 
 receive, via the transceiver, a first response to the first message, the first response to the first message comprising an indication of an identified first guard interval of the plurality of different guard intervals for multi-user uplink WLAN communications; 
 send, via the transmitter, a second message to a second group of stations of the plurality of stations, the second message configured to enable the second group of stations to identify a second guard interval of the plurality of different guard intervals; 
 receive, via the transceiver, a second response to the second message, the second response to the second message comprising an indication of an identified second guard interval of the plurality of different guard intervals for multi-user uplink WLAN communications, wherein the first guard interval and the second guard interval are different guard intervals of the plurality of different guard intervals utilized by a null data packet (NDP) having a same long training field (LTF) during channel sounding. 
 
     
     
       2. The access point of  claim 1 , wherein one of the identified first or second guard interval of the plurality of guard intervals is a longest guard interval of the plurality of different guard intervals. 
     
     
       3. The access point of  claim 1 , wherein:
 the first message comprises a request that each station of the first group of stations perform a time domain channel estimate of a frame received by each station of the first group of stations; and 
 the second message comprises a request that each station of the second group of stations perform a time domain channel estimate of a frame received by each station of the second group of stations. 
 
     
     
       4. The access point of  claim 1 , wherein the first message comprises an indication of the first guard interval of the plurality of different guard intervals and the second message comprises an indication of the second guard interval of the plurality of different guard intervals. 
     
     
       5. The access point of  claim 4 , wherein the LTF utilizes one of the indicated first or second guard intervals. 
     
     
       6. The access point of  claim 1 , wherein the processor is further configured to transmit, by the transceiver, a beamforming report poll associated with the NDP. 
     
     
       7. A station (STA) comprising:
 a transceiver configured to communicate, in a wireless local area network (WLAN); and 
 a processor configured to: 
 receive, via the transceiver, a first message from an access point (AP), wherein the first message is configured to be transmitted to a first group of STAs of a plurality of STAs; 
 identify, based on the first message from the AP, a first guard interval of a plurality of different guard intervals; 
 send, via the transceiver, a response to the first message received from the AP, the response to the first message comprising an indication of the identified first guard interval of the plurality of different guard intervals for multi-user uplink WLAN communications; 
 receive, via the transceiver, a second message from the AP, wherein the second message is configured to be transmitted to a second group of STAs of the plurality of STAs; 
 identify, based on the second message from the AP, a second guard interval of the plurality of different guard intervals; and 
 send, via the transceiver, a response to the second message received from the AP, the response to the second message comprising an indication of the identified second guard interval of the plurality of different guard intervals for multi-user uplink WLAN communications, wherein the first guard interval and the second guard interval are different guard intervals of the plurality of different guard intervals utilized by a null data packet (NDP) having a same long training field (LTF) during channel sounding. 
 
     
     
       8. The STA of  claim 7 , wherein at least one of the guard intervals of the plurality of different guard intervals is compatible with a legacy LTF. 
     
     
       9. The STA of  claim 7 , wherein one of the identified first or second guard interval of the plurality of different guard intervals is a longest guard interval of the plurality of different guard intervals. 
     
     
       10. The STA of  claim 7 , wherein:
 the first message comprises an indication of the first guard interval of the plurality of different guard intervals; and 
 the second message comprises an indication of the second guard interval of the plurality of different guard intervals, wherein the processor is configured to identify the first guard interval and the second guard interval of the plurality of different guard intervals from the indicated guard intervals in the respective first message and second message. 
 
     
     
       11. The STA of  claim 10 , wherein the processor is configured to receive, via the transceiver, the NDP. 
     
     
       12. The STA of  claim 11 , wherein the processor is configured to transmit, via the transceiver, a beamforming report based on the NDP. 
     
     
       13. A method performed by a station (STA), the method comprising:
 receiving a first message from an access point (AP) in a wireless local area network (WLAN), wherein the first message is configured to be transmitted to a first group of stations of a plurality of stations; 
 identifying, based on the first message from the AP, a first guard interval of a plurality of different guard intervals; 
 sending a response to the first message from the AP, the response to the first message comprising an indication of the identified first guard interval of the plurality of different guard intervals for multi-user uplink WLAN communications; 
 receiving a second message from the AP, wherein the second message is configured to be transmitted to a second group of STAs of the plurality of STAs; 
 identifying, based on the second message from the AP, a second guard interval of the plurality of different guard intervals; and 
 sending a response to the second message received from the AP, the response to the second message comprising an indication of the identified second guard interval of the plurality of different guard intervals for multi-user uplink WLAN communications, wherein the first guard interval and the second guard interval are different guard intervals of the plurality of different guard intervals utilized by a null data packet (NDP) having a same long training field (LTF) during channel sounding. 
 
     
     
       14. The method of  claim 13 , wherein at least one of the guard intervals of the plurality of different guard intervals is compatible with a legacy LTF. 
     
     
       15. The method of  claim 13 , wherein one of the identified first or second guard intervals of the plurality of different guard intervals is a longest guard interval of the plurality of different guard intervals. 
     
     
       16. The method of  claim 13 , wherein:
 the first message comprises an indication of the first guard interval of the plurality of different guard intervals; and 
 the second message comprises an indication of the second guard interval of the plurality of different guard intervals, wherein the first guard interval and the second guard interval of the plurality of different guard intervals are identified from the indicated guard intervals in the respective first message and second message. 
 
     
     
       17. The method of  claim 16 , further comprising receiving the NDP. 
     
     
       18. The method of  claim 17 , further comprising transmitting a beamforming report based on the NDP.